Vacuum line diagrams

The PCV runs from the valve cover to (I have no idea) a black thing that has a vacuum tube running out of the top. The vacuum hose coming out of the top is broke off flush and I cannot for the life of me figure out where it goes. It has a lot of vacuum and when I put my finger over it the truck shuts off. My original issue is the truck has been running badly. I had a scan run and says number five cylinder misfire. I have recently replaced plugs, wires cap and rotor. I have good spark on number five and a brand new plug. So in my mind it must be a fuel issue. This morning I decided to put a new injector in the number five cylinder. In the process of taking off the upper intake I broke the cooling line off in the intake, which took a while to fix with out damaging the threads. I ended up fixing a couple other dry rotted lines but have two I am struggling with. By the way, the truck is running extremely rough so I do not know if the injector solved anything but I need to fix the vacuum issues so I can continue the illusive misfire saga. My Monday would really great if I could learn something useful.